Kozinski



Feb. 14, 1956 .J. KOZINSKI ELECTRICAL SYSTEM Filed July 13, 1953 LOAD INVEN TOR. Jasep/z Koz/nsk/ Kama W ATTOQ/VEV United States Patent "on.

2,735,023 Patented Feb. 14, 1956 ELECTRICAL SYSTEM Joseph Kozinski, Chicago, Ill., assignor to H. G. Fischer & Co., Franklin Park, Ill., a corporation of Illinois Application July 13, 1953, Serial No. 367,666

1 Claim. (Cl. 307-112) This invention relates to an electrical system and particularly to a system which may be energized by alternating current at either of two voltages common in power lines. The invention is adapted for use with 60 cycle power lines at potentials of about 110 or about 220 volts. While the system embodying the present invention may be used with other frequencies and at other voltages, the specific examples given are common and are frequently encountered.

While the invention is applicable to a variety of electrical devices and systems, it is particularly adapted for such systems as X-ray systems and other systems which are sufiiciently costly so that the cost of the added equipment required to incorporate the present invention therein will not be too great a factor.

It is well known that in the United States and in many foreign countries, electric power for ordinary use is supplied at 60 cycles or some other suitable frequency and usually at a potential of either about 110 or 120 volts on the one hand or about 220 to 240 volts on the other hand. Within recent years the trend has been to supply many residences and offices with three-wire 220 volt systems, ground being neutral, so that either 110 volt or 220 volt operation may be obtained. For convenience, the figures 110 and 220 will be used although it will be understood that the actual voltages may depart somewhat from these values, in some instances being lower and in other instances being higher than these values. It frequently happens that in places like a doctors office or in hospitals, that receptacles for 110 volts and 220 may be provided. Thus in some rooms or wards there may be one voltage and in other rooms or wards there may be another voltage. It is true that these voltages are usually well marked and in some instances the 220 volt receptacles require 3 prongs.

it is desirable that an X-ray machine or other electrical apparatus be readily usable on either 110 or 220 volt lines Without any adjustment on the part of the user. In many instances, the operator of the X-ray machine is not skilled enough to change connections for using one or the other voltage. in other instances, it may be that oversight or ignorance may result in a machine being plugged into a receptacle for the wrong voltage.

This invention makes it possible to have an electrical machine or device, such as an X-ray system for example, so designed that the operator need not concern himself as to whether the energizing voltage is 110 or 220 volts. A machine embodying the present invention incorporates means for adjusting itself to the voltage supplied and will operate as efliciently at one voltage as at another. Thus a system embodying the present invention places no demands upon the operator in the way of technical skill or care and provides protection against damage to expensive equipment in the event that the wrong voltage is used.

The invention, in general, provides a potential responsive relay which is always connected to the energizing circuit and serves to make the proper connections for supplying current to the input of the machine. For a more thorough understanding of the invention, reference Will now be made to the drawing wherein an exemplary embodiment is illustrated, it being understood that variations may be made without departing from the scope of the invention, except as defined by the appended claims.

The single figure is the diagrammatic illustration of a system embodying the present invention.

Load 10 which may consist of an X-ray system, a motor or any other type of electrical load, is connected to terminals 11 and 12 of autotransformer 13. In the examples specifically illustrated, load 10 is designed for 220 volt operation. Autotransformer 13 has winding 15 having end terminals 11 and 12 and center terminal 16. As will be readily understood, terminals 11 and 16 may be connected for volt energization and terminals 11 and 12 will supply 220 volts. If desired, terminals 12 and 16 may be considered as the input for 110 volt energization.

Transformer terminal 11 is connected by wire 18 to terminal 19. Terminals 19 and 20 are adapted to be connected by contacts 21 and 22 of switch 23 to line cord 24 having plug 25 for insertion into a conventional power receptacle. Connected across terminals 19 and 20 is winding 27 of relay 28. Relay 28 has movable contact 29 operating between normal and off-normal contacts 30 and 31 respectively. Normal contact 30 is connected by wire 32 to center terminal 16. Off-normal contact 31 is connected by wire 33 to terminal 12. Movable contact 29 is connected by wire 34 to terminal 20. Relay 28 is designed so that for 110 volts, movable contact 29 will not be attracted away from normal contact 30 and instead this relay will require 220 volts A. C. for operating the same. Such relays are readily available either for overvoltage purposes or for marginal operation. Thus a relay which will normally require 220 volts to close the same will function satisfactorily providing the spring tension on the movable contact or armature is so adjusted that no operation of the relay at 110 volts is possible.

When plug 25 is inserted into a power receptacle, and switch 23 is closed, relay 28 will either fail to close if the potential is 110 volts or will close if the potential is 220 volts. If the relay fails to close then the 110 volts is applied to terminals 11 and 15 of the autotransformer, the 220 volt output of the autotransformer being supplied to the load. It the relay closes, the 220 volts of the line will be impressed directly upon terminals 11 and 12 and upon the load. It will be clear that relay winding 27 will be connected across the line, irrespective of whether 110 or 220 volts is available. However, the relay winding will be designed so that it will be able to be connected continuously in a 220 circuit without damage. Relay 28 will act sufiiciently fast so that any momentary surge of 220 volts through one-half of the winding, before the relay can close, will cause no damage.

If desired, additional relay contacts may be added to disconnect the autotransformer from terminals 11 and 12 when the relay closes. Instead of an autotransformer, a conventional transformer with separate primary and secondary windings may be used. However, the arrangement disclosed is efficient and satisfactory.

What is claimed is:

An electrical system comprising a load designed for operation at a particular potential at a standard frequency, said particular potential being the higher of two readily available power potentials, an autotransformer having a winding provided with terminals at the ends and with an intermediate tap, one end terminal and said intermediate tap being adapted for energization at the lower of said two available potentials, the outer terminals of said winding being adapted to supply the higher available voltage, connections between the load terminals and the outer terminals of said autotransformer, a connection between said one outer transformer terminal and one power line, a relay having a winding connected across two wires forming a power line for supplying a power voltage which may be either one or the other available voltages, said relay having a movable contact connected to the other power,

line wire and having normal and off-normal contacts connected respectively to the intermediate and other terminals of said autotransforrner, said relay being designed to close only at the higher of the two available voltages and remain open at the lower of said two voltages.

UNITED STATES PATENTS Bronaugh Nov. 24, 1942 Pfeifer June 30, 1931 Kneisley May 9, 1939 Newton Aug. 5, 1941 

